1. Field of the Invention
This invention relates to wind-powered machines. More particularly, this invention relates to wind-powered machines which utilize cup impellers.
2. Prior Art and Other Considerations
Cup-type impellers have long been used for anemometers, which are usually very small meterological instruments utilized to measure wind velocity. Generally, anemometers utilize small generators which have an output that increases constantly with wind velocity. To applicant's knowledge, no serious attempts have been made to utilize cup impellers on large wind machines designed to generate electricity for other uses. One advantage to cup-type impellers is that they rotate at relatively low wind speeds. Accordingly, wind speeds less than ten miles per hour may be utilized to generate electrical current. In addition, cup-type impellers are relatively inexpensive to design and manufacture since they do not require the relatively sophisticated air foil shapes needed for efficient blade-type impellers.
Currently, there is considerable effort being expended to design efficient wind machines which rotate about a vertical axis so that the impellers do not need to be constantly reoriented to face the wind. Most of the arrangements now being considered utilize vertical blades which have complex compound curves and which are difficult to support because the vertical shaft driven by the blades must necessarily be relatively high. By utilizing a cup-type arrangement, the profile of the machine can be lowered considerably.
Cup impellers have not been used on wind machines which rotate a drive shaft about a horizontal axis because the shaft must be continually oriented to face the wind. Accordingly, the advantages of utilizing cup impellers for this type of machine have not been realized.